A radioactive sample has an initial activity of 2.00 $\times$ 10⁶ cpm (counts per minute),and after 4.0 days,its activity is 9.0 $\times$ 10⁵ cpm.What is its activity after 29 days? A)8.7 cpm B)6.1 $\times$ 10³ cpm C)3.3 $\times$ 10² cpm D)1.5 $\times$ 10^-⁹ cpm E)none of these

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Quizplus · Accepted Answer

The decay constant can be calculated using the initial and 4-day activity. Using the decay formula, the activity after 29 days can be calculated, which matches option B.

A Radioactive Sample Has an Initial Activity of 2 ×\times× 106 Cpm (Counts Per Minute),and After 4

A Radioactive Sample Has an Initial Activity of 2 $\times$ 10⁶ Cpm (Counts Per Minute),and After 4